Rick has boards already down on the beach. It's a little choppy, and his instructions are basic: "Okay, you want to get your board parallel to the waves, distribute your weight evenly, and paddle with your elbows locked." That's it.

We walk the boards down to the water. Next thing I know, I'm being toppled by two-foot waves and Rick's nowhere in sight. Oh, there he is, 50 yards out to sea! He has a giant smile on his face, his beard trailing behind him. Rick gives a friendly wave and keeps paddling.

I don't take this personally – this is how he works with bands, too. They talk out songs and then he disappears, only popping in when the band is playing live and for the vocals. Some bands love it; some feel abandoned. Twenty minutes later Rubin sails into shore. I've made no progress except for a slew of bruises on my shins.

He makes an observation. "Maybe it was too windy for your first time."

We hoof the boards back up the beach. He is far ahead of me. I think of Brian Wilson's intense and short-lived health kicks of the 1970s. I ask him if this pace of physical exertion is sustainable for the rest of his life.

"Sure, I'd have to go back to being a totally different person to go back to my old ways. I like who I am now. I would never go back."

But people get tired of their gurus. Wilson eventually got free of his, Dr. Eugene Landy, sick of his mind games and tendency to take songwriting and production credits. Laird Hamilton is famous in his own right, so don't look for him playing percussion on the next Rubin-produced Metallica record, but he seems omnipresent in Rubin's life. We head up the beach, and a muscled middle-aged man appears in front of us. Another Hamilton disciple, he's carrying a 100-pound stone ball. Rubin is intrigued."What's that?" "It's Laird's latest torture device. You pick it up and throw it. That's it." Rick bends at the knees, lifts the orb, and staggers backward. This looks like it's going to end very, very badly. But he regains his footing and tosses the ball onto the hot sand. He's sweating and grinning.

"Laird is nuts. But good nuts."

From the outside, Rick Rubin's house above Zuma Beach is a generic millionaire beach home. There's a rarely used tennis court and a circular drive. Inside, a construction crew is hard at work remodeling a wing of the house. Incense burns.

"I wanted it to be simpler and more open. So I'm turning seven bedrooms into three."

Up the stairs we go. The master bedroom is a new-age space pad. Everything is white.

The white bed is on the white floor. Two nightstands hold identical glass bottles of water in exactly the same spot. There are two giant white beanbag-like contraptions at the foot of the bed. A white tub looks out onto the sea. There's a white toilet in what can best be described as an open floor plan.

"I like things in a certain way. Sometimes I go into someone's office and start rearranging things. Some of them get angry, but most agree that I make the space better."

Rick has never been married and has an unseen girlfriend. ("It's early. I don't want to jinx it.") He owns another mansion in the Hollywood Hills but hasn't slept there in years. We wander into an open room with giant speakers and reams of cable. Rick used to go to L.A. and New York City to produce and mix, but now he does it from home. Songs are dropped into his top-secret, password-protected hard drive with studio-quality sound.

"It's so peaceful here, it's hard to leave. I used to come to Malibu for exactly six hours a week – that's all I could stand. That's all changed."

Rick checks his inbox with a handheld contraption. There's a new mix of a Chili Peppers song that he wants to listen to. We sit on the couch, and Dave appears with glass bottles of water. Rick hits play. Sound blasts us like a rogue wave. He listens with his eyes shut, nodding his head in bliss-filled harmony. Every minute or so, he opens them and taps on an iPhone. When the song ends, he tugs on his beard and reads his notes aloud:

"First verse, vocals a hair loud, guitar on right, in verse after chorus, too noisy, feels like dynamics could be better, verse to chorus is good, but verses get a bit old musically on the way, last chorus isn't a big enough of a step-up from the rest of the song, percussion on the last chorus seems a bit thin, cymbals can shush more than hiss."

He hits a few buttons, and the file is sent back to the band for further revisions. He and the Peppers have worked together for 20 years, and the band is used to his voice-of-God, ultra-hands-off style. But it's not a method that works with everyone: Both U2 and Crosby, Stills & Nash aborted sessions with Rick. Regarding CSN, the producer shrugs his shoulders and says, "They decided it was too much work. They have a certain way they're comfortable with."

Rick Rubin has a comfort level as well. He goes into a project with a specific idea of what he wants to accomplish, though sales are not one of his concerns. "That's not what I'm about. I try to help artists go into a direction that will help build their careers long-term."

We listen to a few more songs before Dave whispers something in Rick's ear. He sighs. "I have a 3 pm meeting." The part of his face not covered with hair makes a face. "And it's in Los Angeles."

About two hours later, I receive a text: I'm back and ready to talk some more. Come over.

It is now nearly dusk, and a cool afternoon wind blows off Zuma. Dave directs me to a spot on the deck. A moment later, Rick emerges.

"How was the meeting?"

"Ugh. It was a meeting."

His face animates as he remembers something.

"Hey, I wanted to show you those meditation exercises you should do before you get out of bed. The ones Serj was talking about."

We lie down on matching deck chairs. Rick begins working his fingers over his face.

"The first one, you want to pull your fingers on your forehead and then pull sort of hard until your hands are placed kinda hard on your windpipe."

For a moment, Rick watches me to see if I'm doing it right. Obviously I'm not, so he slips into his own reverie. He works through the next three with a dreamy smile on his face. Finally, he sits up.

"This last one is a good one. It's called 'galloping horses,' and you start tapping on your head, working all the way back, from top to back."

He's right! It does seem like galloping horses! Dave returns with a snack of apples dusted with cinnamon. I eat a couple before realizing that Rick Rubin still has his eyes closed. Waves crash, bands beckon, and his record company's future remains uncertain. In a week, he will throw his back out exercising. But right now, the streamlined Rick Rubin is somewhere else, galloping into the future.